In general, a driver surveillance system (DSM) or a line of sight tracking technique has been developed for use in advanced driver assistance systems (ADAS).
Meanwhile, although a line of sight tracking technique has been developed as an advanced driver state surveillance, several issues exist that may cause the tracking to fail. For example, if the person whose line of sight is being tracked (e.g., a driver) is wearing glasses, the glass lenses may reflect the light and consequently, the reflected light can cover the cornea reflection point in the person's eye. This can make distinguishing the cornea reflection point from the reflected light difficult. As a result, the line of sight tracking, its marketability and safety may be degraded.